Nonsteroidal anti-inflammatory drugs (NSAIDs)-induced small intestinal injury (enteropathy) occurs in about two-thirds of regular NSAID users. To date, there is no proven-effective treatment for NSAID enteropathy, and its underlying mechanism remains obscure. The present study showed that glucocorticoids are an important determinant of NSAID enteropathy. High dose dexamethasone (DEX, 75 mg/kg) markedly exacerbated the acute toxicity of ibuprofen (IBU, 200 mg/kg) in the small intestine of mice, which was not due to the pregnane-X-receptor pathway. Instead, glucocorticoid receptor (GR) mediated the effect of DEX (5 mg/kg) on both the acute (200 mg/kg) and 7-day repeated-dose (50 mg/kg) toxicity of IBU in the small intestine. Combined treatment of DEX (5 mg/kg) and IBU (50 mg/kg) synergistically repressed the intestinal farnesoid X receptor (FXR)–cystathionine-γ-lyase signaling, which was accompanied with an elevation in the biliary excretion of bile acids, especially the FXR antagonist tauro-β-muricholic acid. DEX (5 mg/kg) also activated intestinal peroxisome proliferator-activated receptor α (PPARα)–UDP-glucuronosyltransferase (UGT) pathway, which increased the formation and enterohepatic circulation of IBU-acyl glucuronide. Furthermore, DEX (5 mg/kg) and IBU (50 mg/kg) altered the intestinal microbial composition, characterized with a marked decrease in Actinobacteria. To conclude, the present study for the first time suggests that glucocorticoids play vital roles in control of IBU enteropathy via intestinal GR–FXR and PPARα–UGT signaling.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2BNQqYy